1. Field of the Invention
The invention relates in general to machines, such as internal combustion engines, power transmissions, and turbines, which use fluids for cooling, heating, lubrication, or power transmission, and more specifically to a heat exchanger tempering valve for use in a motor vehicle coolant system to provide a more consistent coolant temperature to enhance motor efficiency and component longevity.
2. Relevant Background
Machines, like internal combustion engines, power transmissions, and turbines, typically use fluids for cooling, heating, lubrication, or power transmission. These machines usually have an optimum operating temperature at which they operate the most efficiently as far as creating the most power, experiencing the least wear to the parts, and expelling the least unspent fuel in the exhaust. This optimum operating temperature is often determined by controlling the temperatures of the operating fluids.
In an attempt to achieve these optimum operating temperatures, fluids are used to collect or absorb heat from portions of the machines they contact and are then circulated through a radiator or heat exchanger to dissipate the collected, excess heat from the machine. The rate the fluids absorb or transfer heat away from the contacting portions of the machine typically varies widely depending on a number of factors such as the temperature differential between the contacting portions and the cooling fluid and the chemical makeup of the cooling fluid (which may vary over time). The cooling cycle is continuously repeated with the now lower temperature cooling fluid. Unfortunately, the rate a heat exchanger or radiator dissipates heat is generally fixed, e.g., is not adjustable, and the heat exchanger does not compensate changes in the rate a machine develops heat or in heat transfer rates, which results in undesirable fluid operating temperatures and fluid operating temperatures that vary during machine operation leading to fluctuating operating efficiencies and compromised part life.
Automobile engine cooling systems provide excellent examples of the inherent problems of trying to bring a machine to a desired operating temperature and then to maintain an optimum fluid operating temperature for that particular machine, e.g., keeping a cooling fluid or coolant in or near a desired operating temperature range. Liquid cooled engines generally have passages for coolant through the cylinder block and head and has indirect contact with other engine parts such as pistons, cylinders, valve seats and guides. As the coolant flows through the passages, the coolant absorbs heat from the engine parts and then is passed through the radiator to dissipate the absorbed heat (or a portion of the absorbed heat).
During typical operations, once an engine reaches a set operating temperature, a thermostat valve opens fully to circulate all of the engine""s coolant through the radiator. However, this all or nothing approach does not always provide effective control over the coolant temperatures. Often, too much heat is dissipated by the radiator, which results in an engine""s actual operating temperature being below the engine""s optimum operating temperature. Also, the vehicle accessories that rely on hot coolant, such as the heater and defroster, may not operate satisfactorily.
In addition to low operating temperature problems, the engine may produce more heat than the radiator can timely dissipate and the engine overheats to temperatures above the optimum operating temperature or temperature range. If overheating continues, portions of the vital coolant will be lost through a pressure relief system in the radiator cap and the vehicle may be disabled, e.g., components may be damaged and/or the engine may shutdown.
A number of variable factors affect the rate an automobile engine develops heat and the rate an automobile radiator dissipates heat. These factors include load, engine speed, vehicle speed, gear ratio, ground surface condition, rate of climb or decent, acceleration or deceleration, air temperature, wind speed, vehicle direction in relation to wind speed, precipitation, vehicle accessory equipment operation, age and condition of the vehicle, age and condition of the engine fluids. Existing liquid coolant systems are not effective in addressing these numerous heat generation and dissipation variables, and are particularly ineffective in handling fluctuations and rapid changes in these variables.
Hence, there remains a need for a method or system for improving the operation of fluid temperature control systems for machines, such as automobile engines, that provides enhanced control of the operating temperature of the machine by better maintaining the temperature of the fluids within a desired operating temperature range. Preferably such a method and system would be adapted for real time and ongoing control over the coolant temperature because there are a number of variables which constantly factor into the operating temperature of a machine. Further, it is preferable that such a method and system be configured to automatically adjust the rate that heat is dissipated from the machine without operator intervention.
Accordingly it is an object of the present invention to provide an add-on hydraulic system for motor vehicles which, once installed on the vehicle, automatically maintains a consistent optimum operating temperature of the engine coolant, and therefore, the engine, respective of operating conditions.
It is an object of the present invention to provide an add-on hydraulic system for motor vehicles which is universal, and therefore can be added to most vehicles, provided an appropriately-sized system is used.
It is an object of the present invention to provide an easy-to-install system in which the installer can simply splice the system valve and tee into the two radiator hoses and then connect them together with a third hose.
It is further an object of the present invention to provide a fluid temperature maintenance system for machinery which is totally kinetic, without any electrical components, and because of its simplistic design, offers an exceptional level of reliability, durability, and serviceability.
It is additionally an object of the present invention to provide a system that can be easily added to both the coolant and oil systems of a race car, since they typically have independent fluid cooling systems for both fluids.
It is also an object of this invention to provide a fluid temperature maintenance system that is in constant thermal communication with the machine, and rapidly adjusts the rate of heat dissipation as per the immediate needs of the machine.
It is an object of the present invention to provide a fluid temperature control system for a motor vehicle that automatically adjusts to seasonal changes and eliminates any need for mechanical adjustment to the vehicle cooling system to compensate for summer and winter conditions.
Further, it is the object of this invention to provide improved power, improved fuel efficiency, lower exhaust emissions, extended engine oil life, and improved operation of the heater and defroster for a motor vehicle by maintaining the optimum operating temperature of the engine.
Even though the present invention is specifically designed to work with motor vehicles, it also has application with any machine and heat exchanger system that requires temperature maintenance of an integrated fluid.
To achieve the foregoing and other objects and in accordance with the purposes of the present invention, a preferred embodiment of the present invention is a three-port automatic tempering valve that provides a selective bypass of fluid flow through a heat exchanger. When utilized to provide temperature control in an engine cooling system, the valve is installed into an influent line that provides flow to a heat exchanger (e.g., the radiator) from the engine. The automatic tempering valve of the present invention includes a by-pass outlet connection that is piped to a tee installed into the effluent heat exchanger line, which provides flow from the heat exchanger to the engine. In this manner, the automatic tempering valve and connecting piping and components provide a by-pass flow circuit in parallel to the heat exchanger. During operation of the engine, the valve operates automatically to select volumes of flow and direct flow to either the by-pass flow circuit or the heat exchanger. According to an important aspect of the invention, the fluid flow can be selected to be all to the heat exchanger, all to the by-pass flow circuit, and, significantly, concurrently to both the by-pass flow circuit and the heat exchanger. More particularly, depending on the heat dissipation needs of the engine, the automatic tempering valve proportionately divides coolant flow between the by-pass flow circuit and the heat exchanger.
To achieve the proportional flow control feature of the invention, one preferred embodiment of the automatic tempering valve includes a set of thermostatic actuators, such as thermostatic wax motor actuators and the like. The thermostatic actuators are preferably set to actuate sequentially at different temperatures (e.g., a set of predetermined, increasing in magnitude temperatures) and are positioned within a continuous circulation fluid flowstream. The actuators are positioned to act upon a singular proportioning flow diverter within a multiport valve body. During operation, the set of actuators function in combination to provide the total movement of the flow diverter with each thermostatic actuator providing a segment or portion of the total diverter movement with each set at an independent temperature.
In a preferred embodiment, the diverter is spring-loaded toward the cold position (e.g., directing all flow to the by-pass flow circuit to quickly raise the operating temperature of the engine) and the actuators sequentially operate as operating temperature increases to move the diverter toward the hot position (e.g., directing all flow to the radiator). In between the cold position and the hot position, flow is divided between the by-pass flow circuit and the radiator, with more flow being directed to the by-pass flow circuit when the fluid temperature is below the desired or optimum operating temperature or at the lower end of a desired temperature range and more flow being directed to the radiator when the fluid temperature is above the desired operating temperature or at the upper end of the desired temperature range. On an ongoing and real-time basis, the tempering valve reacts to fluctuations in coolant fluid temperature by adjusting the appropriate portion of flow directed into the heat exchanger by the automatic operation of the thermostatic actuators.